Tubulointerstitial fibrosis is a prominent pathological feature of progressive renal disease including diabetic nephropathy. In diabetic nephropathy and other progressive renal diseases, tubular epithelial cells acquire mesenchymal cell characteristics and accumulate matrix proteins that eventuate in fibrosis. Two potential mediators of renal fibrosis in diabetes are high glucose concentrations and transforming growth factor-beta. We have evidence that glucose and TGF-beta inactivate the energy sensor AMPK and that this may result in the cells acquiring mesenchymal cell characteristics and accumulating matrix proteins. The work proposed in this application will utilize in vitro and in vivo approaches to establish if AMPK is indeed a modulator of renal fibrosis and identify downstream signal transduction pathway(s) that may be the effectors of AMPK. Pharmacological and genetic approaches will be used to activate or inhibit AMPK in vitro in cultured tubular epithelial cells and in vivo. For the in vivo studies, we will utlize mice deficient in AMPK specifically in proximal tubular cells. In addition, OVE26 mice with type 1 diabetes will be used to investigate the role of AMPK and downstream signaling pathways including tuberin and mTOR. The central hypothesis of this proposal is that AMPK regulates matrix protein accumulation and mesencymal characteristics of tubular epithelium in diabetes through translational or transcriptional pathways. The studies will help establish adjunct therapy in addition to metabolic control to treat the complications of diabetes.